The speedfan core is very primitive, probably one of the first that Tony created. What it reports is basically useless. One temperature, probably the highest but that is unknown. It does not tell you which sensor is reporting the information.
Speedfan does not identify the sensors in its shared memory area but they are there too query. Either remove the speedfan core or update it.
Severity : MEDIUM
Workaround : None
PS. I can provide a program that does the same as the speedfan core in Xwidget, however it functions a lot better as it reads all of the sensors. It needs to be run from the command line. Xwidget could use it by parsing the output and delivering the results to the widget.

I already use it in my temperature sensing Yahoo widget.
The source code (cpp) is provided so that you can recompile the code yourself if you want to. The code is written in C.